Method of rational-based drug design using osteocalcin

Abstract

The invention relates to a method of identifying a compound that affects osteocalcin activity, comprising obtaining a 3D structure of osteocalcin or a fragment thereof, designing a compound to interact with, or mimic, the 3D structure of osteocalcin or fragment thereof, obtaining the compound, and determining whether the compound affects osteocalcin activity.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application is a continuation of U.S. application Ser. No. 10 / 972,690, filed on Oct. 25, 2004 which claims priority from U.S. provisional patent application No. 60 / 562,237, filed on Apr. 15, 2004 and Canadian application no. 2,446,527 filed on Oct. 23, 2003, both of which are incorporated herein by reference in their entirety.FIELD OF THE INVENTION[0002]The invention relates to the crystalline form of osteocalcin (“OC”). The invention also relates to methods of using the three-dimensional structure of osteocalcin to design and identify candidate compounds that will activate or inhibit osteocalcin activity. The invention also includes compounds identified using the methods of the invention. The invention also includes osteocalcin derivatives that act to inhibit osteocalcin-hydroxyapatite binding. Furthermore, the invention relates to the use of these compounds / derivatives in the treatment of diseases or degenerative conditions resultin...

AI Technical Summary

Benefits of technology

The present invention relates to a crystalline form of mammalian osteocalcin, which is a protein involved in bone mineralization. The invention provides a detailed description of the structure of osteocalcin, including its active site and its ability to bind to hydroxyapatite. The invention also includes a method for identifying compounds that can inhibit or modulate the activity of osteocalcin. The invention has several technical effects, including the ability to design compounds that can mimic the structure of osteocalcin and inhibit its activity, as well as the ability to use the structure of osteocalcin to design new compounds that can interact with hydroxyapatite.

Problems solved by technology

Furthermore, bony metastases of cancers, including breast, prostate and lung cancers, cause pain and potentially death.

There is currently no cure or successful treatment for cancer metastases to bone.

Bisphosphonates are currently being used to treat osteoporosis and other bone disorders, however, their mode of action is poorly understood.

Bisphosphonates consist of two phosphate groups and are structurally analogous to pyrophosphate; therefore, bisphosphonates have the ability to inhibit enzymes that utilize nucleotide trisphosphate and potentially cause cell death.

The activity of bisphosphonates in inhibiting metabolic enzymes and causing cell death is considered to be therapeutic, however it is also likely that they have toxic effects that do not contribute to the therapeutic effects.

However, this has not been proven.

The mechanism of osteocalcin's action has been difficult to elucidate due to, in part, the fact that it has no known enzymatic activities.

Structural determination of small proteins is rather difficult because (i) heavy atom derivatives tend to destroy the crystal and (ii) another method that involves formation of seleno-methionine, which is commonly used, cannot be used because the host that makes seleno-protein (E. coli) can not make Gla.

As well, protein structural aspects, such as a long or flexible C-terminus or N-terminus, can increase the difficulty of crystallization.

The mammalian osteocalcins also have a longer N-terminus and are more difficult to crystallize.

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